Infrared (IR) sensors and associated infrared sensitive inks have traditionally been used for tracking and authenticating a number of different objects. More specifically, labels, barcodes, or other identifiable markings formed from infrared sensitive inks have been formed on the surface of a number of objects. Once marked, objects could then be illuminated with IR light and examined by an infrared sensor to authenticate or track the object.
While traditional methods for tracking and authenticating objects with infrared sensors and associated infrared sensitive inks have been used, these traditional methods have a number of limitations. Specifically, water-based inks containing water soluble IR sensitive dyes have durability and water fastness limitations. Similarly, solvent-based inks containing solvent soluble IR dyes have manufacturing and environmental limitations due to solvent emission. UV curable inks provide unique benefits of print durability as well as environmental friendliness by eliminating solvent emissions. However, many of the IR dyes tend to bleach or experience photo chemical degradation upon exposure to high intensity radiation used for curing UV curable inks.